1. Field of the Invention
The present invention relates to a holder changer, and in particular to a holder changer for automatically changing holders, which are used to transport materials or works to a press and to transport the machined works from the press, in accordance with types of the materials and configurations of the works.
2. Description of the Background Art
In tandem presses, holders of transportation robots have been changed each time the specification for the work is to be changed. This changing operation is carried out by an operator, who enters a central section of a transporter, and the press is stopped during this operation. Therefore, in the press industries which have been required to comply with production of various types but small number of products in recent years, a frequency of change of the holders of robots necessarily increases, which increases the stop time period of the presses, resulting in reduction of the press productivity. Further, since the change of the holders is manually carried out, sufficient measures for achieving the safety of the operator must be applied to the press and peripheral equipments, resulting in increase of the expenses for the equipments and persons.
An object of the invention is to provide a holder changer capable of automatic changing of holders used for transporting materials and works in a press operation.
Another object of the invention is to provide a holder changer which requires a press to be stopped only for an extremely short time period, allows an operator to stay at a safe position remote from a central section of a transporter, and enables change of holders without stopping a press line, e.g., conveyor.